Optimization of WWTP aeration process upgrades for energy efficiency

The volatility of energy prices, desire to improve sustainability, recently proposed legislation, and energy-efficiency project funding have created big opportunities to improve energy and operation efficiency at most water and wastewater facilities. One mechanism of developing these opportunities is through energy management planning. Focusing on wastewater treatment, the majority of electrical energy demand is required for the delivery of air to provide oxygen for biological treatment of waste streams and mixing to suspend solids within process units. Aeration processes can account for 60 percent or more of the overall power consumption at a wastewater treatment plant. Consequently, the recent introduction of direct-drive, high-speed, turbo blowers to the wastewater market has been of great interest with respect to potential energy savings, as well as other ancillary benefits. Given the significant power consumption required by aeration systems at wastewater treatment facilities, demonstration investigations have been conducted to identify the magnitude of energy savings that wastewater treatment facilities could expect. These studies have shown that energy savings in excess of 35 percent can easily be achieved by replacing existing conventional blower technology with direct-drive turbo blowers. Even greater energy savings are anticipated if other process upgrades, such as automatic dissolved oxygen control, is implemented. This paper provides background information on turbo-blower technology and specific findings from demonstration studies in the United States (U.S.).